Objective: To determine if focal ‘nuclear atypia’ or ‘microfollicular architecture’ portends a higher risk of malignancy than other subcategories of atypia of undetermined significance (AUS) in thyroid fine-needle aspirations (FNAs). Study Design: The frequencies of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) categories were calculated from 3,956 thyroid FNAs interpreted over a 26-month period at The Johns Hopkins Hospital after adoption of TBSRTC. TBSRTC criteria were applied strictly. The risk of malignancy, specifically for AUS subcategories, was analyzed by cyto-histo correlation. Results: Of the 133 cases diagnosed as AUS, 32% were found to have stageable carcinoma (not incidental microcarcinoma) on resection. When the subset of AUS with ‘nuclear atypia’ (AUS-N) was separated from other AUS cases, 48% (30/62) of them had stageable carcinoma on resection; of the AUS subset with ‘microfollicular architecture’ (AUS-F), 27% (8/30) were malignant on resection. The ‘suspicious for papillary thyroid carcinoma’ (SPTC) group maintained a higher risk of malignancy versus AUS-N (relative risk, RR 1.57; 95% CI 1.23–1.81). Conclusion: The subcategory of ‘nuclear atypia’ within AUS indicates a higher risk of malignancy than other subcategories of AUS but has a lower risk of malignancy than SPTC does. Thus, it is an important distinction with potential clinical implications.

Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.